When Internet programs like Yahoo Messenger aren't able to connect or send messages, the most likely cause is that the ports it uses aren't open in your router. If, for example, you use Yahoo Messenger at your business to communicate with your employees, it is necessary to get it working again as soon as possible. Fortunately, doing so isn't difficult. To open Yahoo Messenger's ports, you need to go into your router settings and configure port forwarding for the range of ports Yahoo Messenger uses.

Log in to your router's Web-based configuration utility and click the "Port Forwarding" or similarly titled link in the "Advanced" section of the page. Select the "Port Forwarding" option on the following page.

Click the "Add Custom Service" or similarly labeled button on the page and type "Yahoo Messenger 1" in the "Service Name" or "Name" box. Select "TCP/UDP" from the "Protocol" drop-down menu.

Type your computer's IP address in the "Server IP Address" box and then type "5000" in the "Starting Port" box and "5010" in the "Ending Port" box. Click "Apply" or "Save."

Repeat the previous two steps with the following changes: name the service "Yahoo Messenger 2" and type "5050" in both the "Starting Port" and "Ending Port" boxes. Click "Apply" or "Save."

Repeat steps 2 and 3 one more time. This time call the service "Yahoo Messenger 3" and type "5100" in the "Starting Port" and "Ending Port" boxes. Click "Apply" or "Save" and close the configuration utility. Yahoo Messenger should now be able to connect and send messages.

About the Author

Daniel Hatter began writing professionally in 2008. His writing focuses on topics in computers, Web design, software development and technology. He earned his Bachelor of Arts in media and game development and information technology at the University of Wisconsin-Whitewater.